Investigations of the high-pressure phase behaviour of thallium(I) tetradecanoate at pressures up to 250 MPa

Krombach, R.; Schneider, Gerhard

doi:10.1006/jcht.1993.1049

Cited by 3 publications

(3 citation statements)

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“…The same behavior was observed by Lindau et al 20,21 for transitions taking place in TlnC (nϭ2 -22) above room temperature. The transition temperatures measured by these authors agree with our values within the experimental error with the only exception of a transition at 309.7 K for the Tl14C, not seen neither by us nor by Krombach et al 22 For this reason and in order to be clear enough only data for members with nу14 from these authors are included in Fig. 5.…”

Section: Phase Behavior As a Function Of Chain Lengthsupporting

confidence: 88%

A thermophysical study of the melting process in alkyl chain metal n-alkanoates: The thallium (I) series

Cheda

Redondo

García

et al. 1999

The Journal of Chemical Physics

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The peculiar thermal behavior of the thallium(I) n-alkanoates series (consisting in several transitions between polymorphic and mesomorphic phases) in comparison with other metallic n-alkanoates series is stated. The allowance of highly accurate adiabatic heat capacity data permits a study of the CH2 contributions to the lattice heat capacity curve at low temperature. Moreover, in this series an anomalous gradual enhancement of the lattice heat capacity has been interpreted from vibrational spectroscopy results as a noncooperative effect due to the internal hindered rotation of the alkyl chain (formation of gauche defects, even in the solid state). The thermodynamics of the “stepwise melting process” from the totally ordered solid at low temperature to the isotropic liquid is based on a revised lattice heat-capacity curve. This was used to evaluate the energy and entropy not only of the clear first order transitions present in the series but also of the described noncooperative effect. The CH2 enthalpy and entropy contribution for this series is estimated and a comparison with the published values for other series is carried out. Moreover, the texture of the mesophases is revealed by polarized light microscopy.

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Section: Phase Behavior As a Function Of Chain Lengthsupporting

confidence: 88%

A thermophysical study of the melting process in alkyl chain metal n-alkanoates: The thallium (I) series

Cheda

Redondo

García

et al. 1999

The Journal of Chemical Physics

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show abstract

“…The thallium(I) salts of carboxylic acids with α-branching are not mesomorphic, whereas the salts of carboxylic acids with a branch in the β-position exhibit a smectic mesophase. Cheda, Westrum and co-workers determined the heat capacity and the thermodynamic functions of thallium(I) alkanoates by adiabatic calorimetry and by differential scanning calorimetry. − The stability of the neat phase of the thallium(I) alkanoates shows only a limited pressure dependence (up to the experimental limit of 250 MPa) …”

Section: 3 Thallium(i) and Silver(i) Alkanoatesmentioning

confidence: 99%

“…[323][324][325][326][327][328][329][330] The stability of the neat phase of the thallium(I) alkanoates shows only a limited pressure dependence (up to the experimental limit of 250 MPa). 331 Peltzl and Sackmann measured the birefringence (optical anisotropy) and the dispersion (wavelength dependence of the refractive index) of the neat phase of anhydrous thallium(I) alkanoates as a function of the temperature. 332 They made the interesting observation that the optical sign of this uniaxial phase depends on the alkyl chain length.…”

Section: Thallium(i) and Silver(i) Alkanoatesmentioning

confidence: 99%